As a result of the Montreal Protocol phasing out ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), industry has been working for the past few decades to find replacement refrigerants. The solution for most refrigerant producers has been the commercialization of hydrofluorocarbon (HFC) refrigerants. The new hydrofluorocarbon refrigerants, HFC-134a being the most widely used at this time, have zero ozone depletion potential and thus are not affected by the current regulatory phase out as a result of the Montreal Protocol. The production of other hydrofluorocarbons for use in applications such as solvents, blowing agents, cleaning agents, aerosol propellants, heat transfer media, dielectrics, fire extinguishants and power cycle working fluids has also been the subject of considerable interest.
There is also considerable interest in developing new refrigerants with reduced global warming potential for the mobile air-conditioning market.
2,3,3,3-Tetrafluoropropene (CH2═CFCF3, HFC-1234yf), having zero ozone depletion and low global warming potential, has been identified as a potential component in refrigerant blends (see PCT application published as WO 2006/094303). HFC-1234yf has been prepared by reaction of CH2ClC2F5 with zinc in ethanol as reported by Haszeldine and Steele in Journal of the Chemical Society, pages 2193-2197 (1957). There is a need for new manufacturing processes for the product ion of HFC-1234yf.